Diablo, CA Water Safety: 73/100 (2026)
1 ZIP code · 2 water systems · Updated 2026-06-03
In current CA EPA data, Diablo's tap water sits in the high-safety tier.
How Diablo Compares
Data: EPA SDWIS Last verified: 2026-06-03
Key Facts for Diablo Residents
- Homes built before 1986: 53% — older plumbing may contain lead solder.
- Estimated remediation: $3,000 per household.
- CDC health risk index: 10.72.
Diablo's Water Providers
With 2 utilities splitting service in Diablo, CA, water accountability is distributed across 2 systems on the federal record.
Overview
We track water quality and home safety data for 1 ZIP code in Diablo, California (population ~1,000), covering 2 community water systems serving approximately 1,442,950 people region-wide.
No EPA violations recorded across any ZIP codes in Diablo — an excellent indicator of water quality.
Home Safety Score
Average Home Safety Score for Diablo: B (73/100)
The score combines three factors:
| Factor | What It Measures |
|---|---|
| Water Quality | EPA violations and compliance history |
| Lead Levels | 90th percentile lead concentration vs EPA action level |
| Radon Risk | EPA radon zone classification |
Water Sources
Diablo water systems draw from: Groundwater.
Lead & Copper
- Lead data: not yet available for Diablo
- 0 ZIP codes exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 3 (Low Risk)
Areas with No Violations
| ZIP Code | Safety Score | System | Population |
|---|---|---|---|
| 94528 | B | EAST BAY MUD | 1,442,800 |
All ZIP Codes in Diablo
- 94528 [B]
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Lead/copper: EPA Lead and Copper Rule sampling data
- Radon: EPA Map of Radon Zones
Updated daily.
Diablo Community Health Snapshot
Source: CDC PLACES (County-level estimates). Water contamination can correlate with respiratory and chronic health conditions.
Compared to National Average
Vertical line = national average. ■ Above national · ■ Below national
Diablo Infrastructure Age
With 53% of homes built before 1986, lead solder in plumbing is a potential concern. The EPA banned lead solder in 1986, but many older homes retain original plumbing.
Source: U.S. Census Bureau American Community Survey (ACS).
Housing Age Profile
Housing age is one of the most reliable proxies for plumbing-era lead risk, because two federal milestones — the widespread use of lead pipes before 1970 and the continued use of lead solder until 1986 — define the highest-risk tiers of the residential housing stock. With a median build year of 1986, Diablo falls squarely within the older range — meaning a large fraction of the housing was built under the plumbing standards of those earlier eras. The distribution above captures where that risk concentrates, and why older neighborhoods warrant particular attention from residents concerned about tap water quality.
Over half of homes in Diablo were built before 1986, when lead solder was banned. Older plumbing may leach lead into drinking water, especially with corrosive water chemistry.
Source: U.S. Census Bureau ACS B25034.
How Remediation Costs Compare in Diablo
The household financial picture for Diablo homeowners is proportionally favorable — addressing documented issues claims a small slice of equity, and the cost-to-value ratio puts this area well within the manageable tier.
Remediation costs in Diablo are relatively low compared to home values. The $2,100–$4,800 estimated range is a small fraction of median property value. Home values are 171% above the California average.
Diablo: Lead Risk & Vulnerable Populations
Why children are most at risk: The CDC states there is no safe level of lead exposure for children. Children under 6 absorb lead more readily than adults, and even low levels can cause developmental delays, learning difficulties, and behavioral problems.
Despite citywide averages serving as the standard public reference point, those aggregates cannot resolve what is happening at one specific faucet — and where 53% of Diablo homes come from before the solder rule or where utility samples sit at or above the action mark, the gap between system data and faucet reality matters more than it does in lower-exposure communities. An in-home draw closes that gap, with certified filtration through retailer networks available where confirmed faucet results warrant additional measures.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Diablo: Flood History & Water Damage Risk
100% of ZIP codes in Diablo are mapped into FEMA-designated flood zones, and the NFIP records 3 claims reflecting a multi-event flood history. That combination places local flood exposure in the range where water-quality implications deserve at least periodic attention.
Diablo has a moderate flood history with 3 FEMA claims averaging $73,383 per payout. 100% of ZIP codes fall within FEMA flood zones. Flood events can contaminate drinking water and overwhelm treatment systems.
How flooding affects water quality: Flood events can introduce sewage, agricultural runoff, and industrial chemicals into water supplies. Even after floodwaters recede, contamination can persist in wells and aging infrastructure. Flood damage can add significantly to the estimated <strong>$3,000</strong> remediation cost per household.
Residents in flood-prone areas should consider flood insurance even outside FEMA zones — over 25% of flood claims come from low-to-moderate risk areas. After any flood event, test your water before drinking.
Source: FEMA National Flood Insurance Program (NFIP) claims data, FEMA flood zone designations.
Deep Dive Reports
Detailed analysis for Diablo, CA